> the vast, VAST majority of the time you see this message it is actually not a NXDOMAIN error.
I don't have any extensive data as you seem to have but _for me at home_ (= office now!) and without zero captive portal involved, adding this trailing dot reduces the NXDOMAIN frequency from one message every 5 minutes to a few messages _per day_ (NM's default interval is 300 seconds) The "journalctl --boot -p notice" total also becomes about twice smaller. I filed this bug for a reason. > the NXDOMAIN returned by the upstream nameserver is the *correct* response - > that hostname connectivity-check.ubuntu.com.your_domain really, actually > doesn't exist. Yes of course, hence this one character fix which IMHO also removes one large "distraction" from the main, captive portal issue! > if you see this NXDOMAIN "error" [outside a captive portal] it is almost > always just a normal lookup of a domain that doesn't exist, ... which is for sure very rare on my (admittedly headless) system. Not sure why querying inexistent domains would be frequent on others' systems? > and the error message is simply wrong It says "mitigating _potential_..." so it's not strictly speaking wrong. Agreed it can be misleading but summarizing this fairly complex issue in just one line is quite a challenge. > This is due to a Ubuntu-only patch to systemd Care to share the "best" link(s) about this? I mean links to best bugs and/or relevant source code. An internet search returns too many hits! BTW a good and authoritative bug number in the error message would probably not hurt either, see why above. > network-manager could work around this problematic Ubuntu-only systemd patch, With an Ubuntu-only network-manager patch maybe? Sorry couldn't resist :-) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1880258 Title: Add trailing dot to make connectivity-check.ubuntu.com. absolute and reduce NXDOMAIN warning noise Status in network-manager package in Ubuntu: Fix Released Status in systemd package in Ubuntu: Triaged Status in network-manager source package in Focal: Confirmed Bug description: I normally don't like this, but it's a one-character change so it's easier to start with the solution: diff -u -r1.1 /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf --- /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf +++ /usr/lib/NetworkManager/conf.d/20-connectivity-ubuntu.conf @@ -1,2 +1,2 @@ [connectivity] -uri=http://connectivity-check.ubuntu.com/ +uri=http://connectivity-check.ubuntu.com./ Making this name absolute instead of relative avoids spurious resolutions of "connectivity-check.ubuntu.com.your_domain." This removes a fair amount of NXDOMAIN error noise in journalctl. Observing the issue and the fix requires 3 terminals: 1. tcpdump -i any 'port domain' 2. journalctl --boot -u systemd-resolved -f 3. nmcli c down "Wired connection 1"; nmcli c up "Wired connection 1" => observe the NXDOMAIN noise over a couple few minutes Now make the hostname absolute with the trailing dot above and run: systemctl reload NetworkManager Wait 1 min for things to stabilize. Test again: nmcli c down "Wired connection 1"; nmcli c up "Wired connection 1" => observe non-zero but significantly reduced NXDOMAIN noise over a couple few minutes Originally reported at https://askubuntu.com/a/1242611/117217 Plenty of people annoyed by NXDOMAIN warnings, just Google it. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1880258/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
